Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B5/00—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B41/00—Fluid-circulation arrangements
  • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B41/00—Fluid-circulation arrangements
  • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
  • F25B41/24—Arrangement of shut-off valves for disconnecting a part of the refrigerant cycle, e.g. an outdoor part
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
  • F25B2400/07—Details of compressors or related parts
  • F25B2400/075—Details of compressors or related parts with parallel compressors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
  • F25B2400/13—Economisers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
  • F25B2400/22—Refrigeration systems for supermarkets
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B5/00—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity
  • F25B5/02—Compression machines, plants or systems, with several evaporator circuits, e.g. for varying refrigerating capacity arranged in parallel

Definitions

• This application relates to a refrigerant cycle utilizing tandem compressors sharing a common condenser, but having separate evaporators.
• Refrigerant cycles are utilized in applications to change the temperature and humidity or otherwise condition the environment.
• a compressor delivers a compressed refrigerant to an outdoor heat exchanger, known as a condenser. From the condenser, the refrigerant passes through an expansion device, and then to an indoor heat exchanger, known as an evaporator. In the evaporator, moisture may be removed from the air, and the temperature of air blown over the evaporator coil is lowered. From the evaporator, the refrigerant returns to the compressor.
• basic refrigerant cycles are utilized in combination with many configuration variations and optional features. However, the above provides a brief understanding of the fundamental concept.
• tandem compressors In more advanced refrigerant cycles, a capacity of the air conditioning system can be controlled by the implementation of so-called tandem compressors.
• the tandem compressors are normally connected together via common suction and common discharge manifolds. From a single common evaporator, the refrigerant is returned through a suction manifold, and then distributed to each of the tandem compressors. From the individual compressors the refrigerant is delivered into a common discharge manifold and then into a common single condenser.
• the tandem compressors are also separately controlled and can be started and shut off independently of each other such that one or both compressors may be operated at a time. By controlling which compressor is running, control over the capacity of the combined system is achieved.
• tandem compressors may have shutoff valves to isolate some of the compressors from the active refrigerant circuit, when they are shutdown.
• pressure equalization and oil equalization lines are frequently employed.
• tandem compressor is that better capacity control is provided, without the requirement of having each of the compressors operating on a dedicated circuit. This reduces the overall system cost.
• cooling at various temperature levels For example, low temperature (refrigeration) cooling can be provided to a refrigeration case by one of the evaporators connected to one compressor and intermediate temperature (perishable) cooling can be supplied by another evaporator connected to another compressor.
• a computer room and a conventional room would also require cooling loads provided at different temperature levels, which can be supplied by the proposed multi-temp system as desired.
• the cooling at different levels will not work with application of a conventional tandem compressor configuration, because a separate evaporator for each cooling level would be required.
• non-tandem independent compressors must be used in a dedicated circuit for each cooling level.
• each circuit must be equipped with a dedicated compressor, dedicated evaporator, dedicated condenser, and dedicated condenser fans. This arrangement having a dedicated circuitry for each temperature level would be very expensive.
• This invention offers a solution to this problem where tandem compressors can be used for operating a refrigerant system at multiple distinct temperature levels.
• evaporators for each separate area.
• Each of the evaporators communicates with a separate compressor, while the compressors send compressed refrigerant through a common discharge manifold to a common condenser.
• a separate environmental control in each of the cooling zones is achieved, and there is no necessity of providing a complete set of the components of two individual refrigerant circuits (such as an additional condenser and additional condenser fans).
• tandem compressors can operate at each additional temperature level associated with the added compressor.
• operation at three temperature levels can be achieved by connecting each of the three compressors to a dedicated evaporator.
• two out of the three compressors can operate with common suction and discharge manifold and be connected to the same evaporator, while the third compressor can be connected to a separate evaporator.
• the tandem application can be extended in an analogous manner to more than three compressors.
• Figure 1 shows the prior art.
• Figure 2 is a first schematic.
• Figure 3 is a second schematic.
• a conventional prior art multi-level (bi-level in this case) system 10 is shown to include two separate circuits 11 to serve subsections of the environment at different temperature levels.
• Each basic circuit 11 includes a dedicated evaporator 17, condenser 15, compressor 13, expansion device 14, condenser fan 16, evaporator fan 18 and associated piping.
• each circuit can be controlled to maintain a desired evaporator temperature by various means and thus provide multi-level cooling to the environment.
• such conventional approach is cumbersome and requires a significantly higher cost for system manufacturing and operation.
• a refrigerant cycle 20 is illustrated in Figure 2 having a pair of compressors 22 and 23 that are operating generally as tandem compressors.
• Optional valves 26 are positioned downstream on a discharge line associated with each of the compressors 22 and 23. These valves can be controlled to prevent backflow of refrigerant to either of the compressors 22 or 23 should only one of the compressors b>e operational. That is, if for instance compressor 22 is operational with compressor 23 stopped, then the valve 26 associated with compressor 23 will be closed to prevent flow of refrigerant from the compressor 22 back to the compressor 23.
• the two compressors communicate with a discharge manifold 29 leading to a common condenser 28.
• the refrigerant continues downstream and is split into two flows, each heading through an expansion device 30.
• one of the flows passes through a first evaporator 32 for conditioning a sub-environment B.
• the refrigerant passing through the evaporator 32 passes through an optional suction modulation valve 34, and is returned to the compressor 22.
• the second refrigerant flow passes through an evaporator 36 that is conditioning a sub-errvironment A.
• This refrigerant also passes through an optional suction modulation valve 34 and is returned to the compressor 23.
• a control 40 for the refrigerant cycle 20 is operably connected to control the compressors 22 and 23, the expansion valves 30, suction modulation valves 34 and valves 26.
• the conditions at each evaporator 32 and 36 can be controlled as necessary for the sub-environments A and B.
• the exact controls necessary are as known in the art, and will not be explained here.
• the use of the tandem compressors 22 and 23 utilizing a common condenser 28 reduces the number of components necessary for providing the independent control for the sub- environments A and B, and thus is an improvement over the prior art.
• FIG. 3 shows a more complicated refrigerant cycle 50 for conditioning three sub-environments A, B and C.
• a single condenser 52 communicates with a discharge manifold 51.
• a first compressor 54 also communicates with the discharge manifold 51.
• a second compressor bank 56 communicating with the same discharge manifold 51, includes two tandem compressors which each communicating with a suction manifold 65.
• a third compressor bank 58 once again, communicating with the discharge manifold 51, includes three compressors all operating in tandem and communicating with a suction manifold 67.
• the control of the compressor banks 56 and 58 may be as known in the art of tandem compressors. As mentioned above, by utilizing the compressor banks 56 and 58, a control over the temperature in each of the sub-environments B and C is provided.
• the refrigerant passes through separate expansion devices 60, and to separate evaporators 62, 64 and 66.
• evaporator 62 conditions the air heading into a sub-environment A
• evaporator 64 conditions the air heading into a sub- environment B
• evaporator 66 conditions the air heading into a sub-environment C.
• Optional suction modulation valves 70 are positioned on each of the suction lines returning to the compressors 54, 56 and 58.
• a control 72 is provided that controls each of the elements to achieve the conditions within each of the sub-environments A, B, and C. The individual control steps taken for each of the sub-environments would be known. It is the provision of the combined multi-level system utilizing a common condenser and tandem compressors that is inventive here.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Air Conditioning Control Device (AREA)
• Compression-Type Refrigeration Machines With Reversible Cycles (AREA)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

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Citations (5)

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• 2004
  • 2004-10-28 US US10/975,887 patent/US20060090505A1/en not_active Abandoned
• 2005
  • 2005-10-21 WO PCT/US2005/037692 patent/WO2006049883A2/en active Application Filing
  • 2005-10-21 JP JP2007538993A patent/JP2008518194A/ja not_active Withdrawn
  • 2005-10-21 EP EP05817050A patent/EP1805462A4/de not_active Withdrawn

Patent Citations (5)

Non-Patent Citations (1)

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